1. Field of the Invention
This invention relates, generally, to machinery. More particularly, it relates to a swale-digging machine that may be towed by a tractor.
2. Description of the Prior Art
A swale can be a natural depression formed in land. It can also be a man-made depression such as an elongate ditch. For example, a swale may be formed in farmland to collect rainwater as a water conservation measure. In an orange grove formed by multiple rows of orange trees, an elongate man-made swale may be formed between each row of trees so that each row of trees grows in dry ground that is elevated relative to a swale on each side of each row. The swale collects rainwater and each tree can draw upon the water in the swale as needed. In this way, the earth directly under the branches of the tree remains dry as required for the health of the tree. Advantageously, the trees that benefit from the swale provide shade which decreases the rate of water evaporation from the swale.
Several tools for digging swales have been invented, but they operate very slowly, traveling at speeds less than a quarter mile per hour. Moreover, some of the known devices form swales having steep banks with the removed earth stacked at the top of the banks. These swales re-fill when rain causes the stacked earth to slide down the steep banks.
Thus there is a need for a swale digging machine that operates at a faster rate of speed than the known machines, which builds swales having banks that are not steep, and which does not stack the removed earth at the top of the banks where it can be washed back down into the swale by rainfall.
However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the art how the needed structure could be provided.